This invention relates generally to a subsea wellhead connection assembly for establishing fluid communication between a subsea wellhead and an adjacent subsea manifold assembly. In particular, the invention relates to a connection assembly for use in such a well system for handling oil and/or gas production from a multiplicity of subsea wells which are fed into a common point for subsequent transfer to a collection facility on the surface of the water.
The assignees of the present invention have developed a template for such an undersea collection system as disclosed in their copending applications, as will be later discussed.
In such subsea assemblies it is usual to have a horizontal platform or template adjacent to the sea bottom and of a generally circular configuration with a fluid tight work enclosure hull in the center of the template having a plurality of radially disposed lateral connectors or penetration means adapted to be connected to conduits coming from undersea wellheads. The wellhead connections pipes are usually brought to the underside of the template and face vertically upward. The template is divided into a plurality of radially extending generally pieshaped segments which are separated from each other by vertical partitions, usually in the form of welded pipes so as to define a group of stations, usually ten in number, which are circumferentially spaced about the template, radially outward of the previously mentioned center work enclosure hull. Such an underwater structure is preferably assembled in disconnectable portions which can be brought to the surface for repair and/or replacement as necessary.
The present assignee has copending U.S. patent application Ser. No. 343,634 filed Jan. 28, 1982 and application Ser. No. 371,901 filed Apr. 26, 1982 which are directed to related structures.
The wellhead connector assembly disclosed in copending application Ser. No. 371,901 comprises a body made up of a framework of about 3" diameter pipe or tubing welded or bolted together so as to form an upstanding frame, which is generally rectangular in side view and of a trapezoidal shape when viewed from the top. There is a centrally disposed wellhead connector means which forms the main connection going to the wellheads.
In that invention, wellhead connector 45 does not attach directly to wellhead 14, but is connected to a master valve assembly 50, which is secured to wellhead 14 for providing well shut-down capability and protection before the well is connected to manifold 39 within work enclosure hull 13. Master valve assembly 50, which may be of conventional construction, is installed on base template 11 before work enclosure hull 13 is installed. Connection is made to the penetration means by a laterally moveable manifold connector, which is connected to the wellhead connector by a loop of pipe.